Acaulospora punctata, a new fungal species in the Glomeromycetes from mountainous altitudes of the Swiss Alps and Chilean Andes

A new species of the genus Acaulospora (Glomeromycetes) was found in several mountainous to high mountainous grasslands in Switzerland and Southern Chile, at 1850-2050 m and 550-1600 m asl, respectively. The species has yellow-white to creamy and regularly globose to subglobose spores with a diameter of 105-129 mu m. It is characterized by an ornamentation on the outer surface of the outer spore wall with point-like, concave and highly regular pits that are 1.1-2.0(-2.7) mu m in diameter and at least as deep (1.4-3.5 mu m) as wide. Phylogenetic analyses compiling partial sequences of the ITS of the ribosomal DNA place the species adjacent to A. cavernata, A. denticulata, A. paulinae and A. sieverdingii. The new fungus is described here under the epithet A. punctata. Many spores of the fungus were detected in the foreland of the retreating Morteratsch glacier near St. Moritz (Engadin, Switzerland) particularly in pioneer stands dominated by Epilobium fleischeri but also in plant-species rich older grasslands in larger distance to the glacier. It was also found in mountainous managed forests and grasslands in Southern Chile suggesting the worldwide distribution of the fungus in mountainous regions.